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PremierWave centre-tap wiring details

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  • PremierWave centre-tap wiring details


    My colleague would like some details of the centre-tap terminals of the PremierWave mating connector. He is testing 1:1 Ethernet transformers between a PremierWave and a third party SoM. Unfortunately he cannot connect a white wire to the mating connector, so instead he would like to replicate the circuitry on the PremierWave associated to the centre-tap terminal. He is trying to work out if the centre-tap is tied to ground or the Ethernet supply. Please see his email below...

    To Lantronix support,

    my colleague, Matthew, recently made an enquiry regarding the connection of a PremierWave wifi module to a Karo SoM, using magnetic-less capacitive coupling. He provided a diagram of the method that had been utilised to connect the ethernet PHYs of the respective modules.
    Refer to attachment Magnetic-less Designs.pdf

    A decision had been made to replace capacitive coupling with 1:1 ethernet transformers between the two PHYs. Please refer to attachment Karo to PremierWave ethernet transformer coupling.pdf. This method will utilise a single winding between each of the transmit and receive pairs. We are endeavouring not to have to use the standard common mode chokes.

    At this stage we have modified our PremierWave baseboard to accommodate the transformers. Our testing so far has indicated some errors.

    The centre-taps of the transformers have been terminated on the Karo side according to their recommendations. Refer to attachment. As yet the centre taps on the PremierWave side have not been terminated. This is because the centre-tap terminals of the PremierWave mating connector on the base board are difficult to attach wires to. Could you please provide details of how the centre-tap connections are terminated on the PremierWave module. I will implement this for testing purposes on the base board.

    For production manufacture, new base board PCB artwork will be generated that will connect the centre-taps of the transformers directly to the corresponding terminals of the PremierWave mating connector, pins 69 and 71. But I would like to test and confirm this before committing to large production quantities.

    Thank you

    Best Regards, Anthony.